The present invention relates to a stop device for a door lock and, more particularly, to a stop device for a door lock mounted on a panic exit door to prevent the panic exit door from being opened due to high heat of a fire to prevent the spread of fire and smoke.
A typical lock for a panic exit door generally includes a press bar that can be pressed to retract a latch for unlatching the door in emergency conditions as well as for normal passage. The lock can be locked to prevent unauthorized access and can be unlocked by a key from an outer side of the door. When a fire occurs, the panic exit door should remain in the closed position to avoid the spread of fire and smoke. In an approach, the lock includes a locking member slideable between a first position allowing pressing of the press bar and a second position not allowing pressing of the press bar. However, the locking member can be inadvertently moved to the first position by high-pressure water or steam transformed from the water for extinguishing the fire, resulting in the risk of opening of the panic exit door.
Thus, a need exists for a panic exit door lock that can be reliably maintained in the closed position during a fire.